Neil Young recorded the soundtrack by improvising (mostly on his electric guitar, with some acoustic guitar, piano, and organ) as he watched the newly edited movie alone in a recording studio.
Nobody (Gary Farmer) can be heard several times to exclaim, "Hootka!" or "Huht-kah!" According to Farmer, it's not an actual word, but slang for, "What the fuck?!" or simply, "Fuck!"
This movie contains conversations in the Cree and Blackfoot languages, which were intentionally not translated or subtitled, for the exclusive understanding of members of those nations, including several in-jokes aimed at Native American viewers.
The line said by Nobody, "The eagle never lost so much time as when he submitted to learn from the Crow", is also a William Blake quote, from the proverbs of Hell in "The Marriage of Heaven and Hell".